The heavy concrete refers to a concrete having a larger weight per unit volume than a typical one, and is used as a wave-dissipating block, a concrete for a river/sea wall, a radiation shielding wall, a bridge weight, and the like. Although iron ores such as magnetite and hematite have been frequently used as heavy aggregates to be used in heavy concretes, it is gradually becoming difficult to obtain high-quality ones as heavy aggregates, and usage of valuable natural resources are undesirable from an economical standpoint as well as an environment-conscious standpoint. Further, heavy concretes have been proposed which utilize coarse particle components sieved from steelmaking converter dusts, as fine aggregates instead of iron ore aggregates, for example (see Patent Document 1).
However, in case of adopting the iron ores as heavy aggregates and in case of adopting the alternatives such as coarse particle components of steelmaking converter dusts as heavy aggregates, such a problem has been caused that segregation is likely to occur between a heavy aggregate and a cement paste due to a large difference of specific gravity therebetween. As such, there has been conventionally conducted addition of a thickener such as methyl cellulose into a heavy concrete, so as to restrict a segregation between a heavy aggregate and a cement paste (see upper left column on page 3 of Patent Document 2, for example). However, addition of a thickener delays a hydration reaction of a cement, so that addition of the thickener in a large amount is undesirable. Thus, there has been demanded a heavy concrete, which does not require addition of a thickener such as methyl cellulose, which is less in segregation between a heavy aggregate and a cement paste, and which is high in flowability and excellent in construction ability.    Patent Document 1: JP-5-319880A    Patent Document 2: JP-62-158181A